One type of semiconductor package is referred to as a multi chip module. A typical multi chip module includes a substrate having an interconnect pattern for mounting one or more bare dice. A cover or encapsulant can also be formed on the substrate for protecting the dice. Different techniques can be used for mounting the dice to the substrate, and for providing electrical interconnection and termination of the dice. These techniques include wirebonding, tape automated bonding (TAB), micro-bump bonding, and flip chip bonding.
Multi chip modules can also be fabricated using packages adapted to contain and electrically contact bare dice. One type of package used to form multi chip modules is referred to as a connector. A connector can include a housing with individual channels for receiving the dice, and spring contacts for electrically contacting the bond pads on the dice. Typically the dice include bond pads formed along one edge. Dice having bond pad configurations configured for this type of packaging are sometimes referred to as a direct die contact (DDC) dice.
A representative connector is available from AMP Inc. of Harrisburg, Pa., and is described in U.S. Pat. No. 5,104,324 to Grabbe et al. entitled "Multi Chip Module Connector". With this type of connector, the dice are slid into channels into physical contact with spring contacts. The spring contacts scrub the surfaces of the device bond pads to penetrate electrically insulating native oxide layers, and contact the underlying metal.
One problem with this type of connector is that the quality of the electrical connections with the device bond pads is dependent on contact forces developed by the spring contacts. If the contact forces aren't sufficiently high, reliable electrical contacts cannot be achieved. However, the spring contacts can also exert too much force and damage the dice. The bond pads and passivation layer of a (DDC) die are particularly susceptible to damage during insertion into the separate channels of the connector. In a similar manner the dice cannot be removed from the housing without damage.
Another problem with this type of connector, is "misalignment" occurring between the spring contacts and bond pads. In particular, flexing and binding of the spring contacts can cause misalignment with the bond pads. Another problem, referred to as "fretting", can occur if the spring contacts move or vibrate with respect to the bond pads. Misalignment and fretting can affect the quality of the electrical connections and cause damage to the dice.
In view of the foregoing improved direct die contact (DDC) semiconductor packages are needed.